LangRef: Clarify semantics of lround/llround and lrint/llrint

[nlopes]

Thanks.
unspecified is not a term used in LLVM IR semantics. I would write, for example, "a non-deterministic value (equivalent to freeze poison)".

[arsenm]

Rephrase

[nlopes]

LGTM

[aqjune]

The clarification looks good to me as well, thanks.
Since LLVM IR does not have a notion of unspecified value (AFAIK), defining these as returning a nondeterministic, well-defined value seems like a right choice because it satisfies refinement.
Making them return an undefined value or poison value breaks refinement.

[arsenm]

ba5c26da7ce85dbdcee3d964282e5f0981792702

llvm/docs/LangRef.rst

 """"""""""
 
 The argument is a floating-point number and the return value is an integer
 type.
 
 Semantics:
 """"""""""
 
-This function returns the same values as the libm ``lround``
-functions would, but without setting errno.
+This function returns the same values as the libm ``lround`` functions
+would, but without setting errno. If the rounded value is too large to
+be stored in the result type, the return value is a non-deterministic
+value (equivalent to `freeze poison`).
 
 '``llvm.llround.*``' Intrinsic
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Syntax:
 """""""
 
 This is an overloaded intrinsic. You can use ``llvm.llround`` on any

 
 The argument is a floating-point number and the return value is an integer
 type.
 
 Semantics:
 """"""""""
 
 This function returns the same values as the libm ``llround``
-functions would, but without setting errno.
+functions would, but without setting errno. If the rounded value is
+too large to be stored in the result type, the return value is a
+non-deterministic value (equivalent to `freeze poison`).
 
 '``llvm.lrint.*``' Intrinsic
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Syntax:
 """""""
 
 This is an overloaded intrinsic. You can use ``llvm.lrint`` on any

 """"""""""
 
 The argument is a floating-point number and the return value is an integer
 type.
 
 Semantics:
 """"""""""
 
-This function returns the same values as the libm ``lrint``
-functions would, but without setting errno.
+This function returns the same values as the libm ``lrint`` functions
+would, but without setting errno. If the rounded value is too large to
+be stored in the result type, the return value is a non-deterministic
+value (equivalent to `freeze poison`).
 
 '``llvm.llrint.*``' Intrinsic
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Syntax:
 """""""
 
 This is an overloaded intrinsic. You can use ``llvm.llrint`` on any

 """"""""""
 
 The argument is a floating-point number and the return value is an integer
 type.
 
 Semantics:
 """"""""""
 
-This function returns the same values as the libm ``llrint``
-functions would, but without setting errno.
+This function returns the same values as the libm ``llrint`` functions
+would, but without setting errno. If the rounded value is too large to
+be stored in the result type, the return value is a non-deterministic
+value (equivalent to `freeze poison`).
 
 Bit Manipulation Intrinsics
 ---------------------------
 
 LLVM provides intrinsics for a few important bit manipulation
 operations. These allow efficient code generation for some algorithms.
 
 '``llvm.bitreverse.*``' Intrinsics